ET to IRST Time Converter
IRST is 7 hours and 30 minutes ahead of ET. The US East Coast is currently on EDT (UTC-4:00), and IRST is UTC+3:30.
Best Time to Call Between ET and IRST
Both zones are inside normal business hours between 9:00 AM and 10:00 AM ET — that's 4:30 PM to 5:30 PM IRST. That's a 1-hour window.
both at work ET only IRST only neither — hours along the strip are ET.
Common Times Converted
ET on the left, IRST on the right.
ET to IRST: Full 24-Hour Conversion Table
Shaded rows are working hours; the darker shade marks the hours when both zones are at work.
| ET | IRST | Working hours |
|---|---|---|
| 12:00 AM | 7:30 AM | — |
| 1:00 AM | 8:30 AM | — |
| 2:00 AM | 9:30 AM | IRST only |
| 3:00 AM | 10:30 AM | IRST only |
| 4:00 AM | 11:30 AM | IRST only |
| 5:00 AM | 12:30 PM | IRST only |
| 6:00 AM | 1:30 PM | IRST only |
| 7:00 AM | 2:30 PM | IRST only |
| 8:00 AM | 3:30 PM | IRST only |
| 9:00 AM | 4:30 PM | Both zones |
| 10:00 AM | 5:30 PM | ET only |
| 11:00 AM | 6:30 PM | ET only |
| 12:00 PM | 7:30 PM | ET only |
| 1:00 PM | 8:30 PM | ET only |
| 2:00 PM | 9:30 PM | ET only |
| 3:00 PM | 10:30 PM | ET only |
| 4:00 PM | 11:30 PM | ET only |
| 5:00 PM | 12:30 AM next day | — |
| 6:00 PM | 1:30 AM next day | — |
| 7:00 PM | 2:30 AM next day | — |
| 8:00 PM | 3:30 AM next day | — |
| 9:00 PM | 4:30 AM next day | — |
| 10:00 PM | 5:30 AM next day | — |
| 11:00 PM | 6:30 AM next day | — |
What ET and IRST Actually Are
ET — Eastern Time
New York, Toronto, Washington DC, Atlanta, Miami, Boston. Standing at UTC-5:00 as written, and the region does change its clocks, so its live offset moves by an hour twice a year. The next change is on Sunday, November 1, 2026, to EST.
Eastern Time covers roughly half the US population and, because of that, is the zone most American business defaults to when nobody specifies one.
IRST — Iran Standard Time
Tehran, Mashhad, Isfahan. Standing at UTC+3:30 as written, and the region does not change its clocks, so that offset holds all year. Iran abolished daylight saving in 2022, so the half-hour offset now holds all year.
Iran abolished daylight saving in 2022. Its half-hour offset is a deliberate compromise between the solar times of its western and eastern borders.
What This Means in Practice
Expect times on the half hour
IRST sits on a 30-minute offset rather than a whole hour, so a round number on one side is never a round number on the other. A 9:00 meeting becomes 30 minutes past the hour, which is exactly the detail calendar invitations get wrong when someone converts in their head.
This gap is not fixed
ET changes its clocks and IRST does not, so the difference between them moves by an hour twice a year. A recurring meeting set now will drift for one side from Sunday, November 1, 2026 unless someone resets it.
Major Cities in Each Zone
Cities on ET
Cities on IRST
Frequently Asked Questions
What is the time difference between ET and IRST?
IRST is 7 hours and 30 minutes ahead of ET. That is the live figure. Taken strictly as written, the gap between ET and IRST is 8 hours and 30 minutes — the two differ because at least one of these regions is currently on daylight saving.
What is 9:00 AM ET in IRST?
9:00 AM ET is 4:30 PM IRST.
What are the best hours to schedule a call between ET and IRST?
Between 9:00 AM and 10:00 AM ET, which is 4:30 PM to 5:30 PM IRST. Both sides are inside normal business hours through that window.
Does the difference between ET and IRST change during the year?
Yes. ET observes daylight saving and IRST does not, so the gap shifts by an hour at least twice a year. The next clock change is on Sunday, November 1, 2026.
Does IRST always mean Iran Standard Time?
Iran abolished daylight saving in 2022, so the half-hour offset now holds all year.